gui option for "hudson.model.WorkspaceCleanupThread.disabled"
WorkspaceListener to accept Job/Run
removing a job (including multibranch/org folder branches/repos) does not remove the workspace
JENKINS-35907 might be useful for implementation.
The implementation of JENKINS-2111 (currently in branch-api but could be made independent) subsumes the important functions of WorkspaceCleanupThread, I think in a more reliable way, so it could perhaps simply be deleted.